Looking at building a subwoofer with a peerless xls10 and either 1 or 2 10" peerless Passive radiators.

Now i have been playing around with unixbox and i have come up with the following design based on the xls10 and 1 passive radiator.

The first design i came up with was a 32l enclosure with the xls10 and 1 passive radiator. Now this should give response down to 27hz before the the passive radiator hits max excursion. I have attached a graph of this design.

Now i assumed that if i could use 2 passive radiators then i should be able to come up with a design that gets me down to around 20hz, but playing with unibox i cant seem to come up with a design that will get me to that goal.

Can anyone suggest a way of getting down to 20hz using the 2 passive's and the XLS10?

Hi,
I ran the sub you want with two passive radiators on unibox and came up with a design that will give good response down to 20Hz, but the box would be be large (70 litres). What weight PR did you input? 400 grams is what I tried. Adding weight to the PR will lower FB, but you give up some efficiency.

I am using 265g passive radiators. I didn't really want to go over say 50l for box size. Maybe i am being to optimistic about the response down to 20hz, maybe i should aim a little higher (although 20hz would be nice!).

I've found that the excursion shown in the software doesn't directly relate to the real world in most cases. I have FR drivers that should hit the stops at less than 1W but are still powering at 30W.... program material is different. There was a thread in the FR section recently about this.

Smaller box means adding mass to passives. This will also reduce excursion. Your 265 gram PR is more suited to a smaller driver, its too light for what you want. Its easy- add weight to the passives in unibox untill you get the response where you want it with the box size you want.